EDIT: Gadget Boy has kindly renamed the thread on my request. It started out as "Which engine would you swap into a LC4 Adventure frame" and has since turned into a bit more than just another stupid idea of mine.

Hey guys,

I have been looking for a new project bike to add to the stable and came across an '98 LC4 Adventure rolling chassis. Seems like a cool base to start from as I always loved the bike but didn't trust it after my last LC4 blew up on me. With my DR650 (that I will keep) I went the other way and changed out pretty much everything but the engine, so this will be an interesting contrast.

Here is what I am thinking in terms of criteria (I reserve the right to change my mind at any given moment ):

1. Frame fitment: Engine mounts are no problem, but I'd like to avoid major surgery to the frame tubes if possible. So I'd guess that excludes most twins (at least the V's) unfortunately. It would also be an advantage if the output shaft was mounted on the right.

2. Proven reliability: Absolutely critical. I can deal with issues that are known and can be changed out in advance (like base gasket NSU screws on the DR) but not a critical engine/gearbox failure without warning. Sorry to all you orange Kool-Aid drinkers, but that excludes the LC4.

4. Fuel economy: FI (as long as it's reliable) would be a big bonus here. I like to twist the throttle and with the highway speeds over here even the bone stock DR engine with vacuum carb sucked fuel like crazy. I'd say 55+ mpg in mixed riding would be a good goal.

5. Performance: I like torque and a decent top speed even when loaded. I am thinking 600cc+.

I realize that engine swaps are always a loosing proposition as far as time and monetary investment go, but I enjoy wrenching almost as much as riding.

Please add some pros and cons to your choice in regards to the criteria stated above.

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Ahhhh I thought we were just having a brainstorming session

Well, The pros of the 800 engine are known, think of an overbuilt dr650 engine. In terms of consumption I doubt it is as bad as you rate the dr650. With standard gearing on motorway doing an indicated 140 it returns about 7lts/100km if jetted properly. The gearbox ratio is 3.0 which is not too bad.
The cons are weight, it weighs about 60kgrs.

Having said all that, I think the most fun engine you could have is probaby that of the versys, but I'm not sure how easy it is to fit due to width. As far as single cylinder engines go, the 800 is the dog's bollocks. A guy here in greece has fitted it in a yz450 frame for the supermto championship. There is a thread here in advrider with some pics of it.

And a completely of the wall idea I have seen done in both an xt600 frame and an lc4 frame. A bmw boxer airhead 800.

.....
2. Proven reliability: Absolutely critical. I can deal with issues that are known and can be changed out in advance (like base gasket NSU screws on the DR) but not a critical engine/gearbox failure without warning. Sorry to all you orange Kool-Aid drinkers, but that excludes the LC4. ....

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I take it that means the Husaberg 650 motor is out. Too bad, that'd rip.

I was thinking of this the other day. The Xchallenge motor seems ideal, but the single exhaust outlet on the head may interfere with the frame downtube. Ditto the downdraft intake and the top tube.

A parallel twin would be great. A gs500 motor, or an ex500 motor like the Webers' Rallye Twin used. Good luck fitting the tank over either of them, though.

As far as reliability, the fussier motors might do better than usual in this setup because you have the extra oil reservoir and filter to add on.

If it were me I'd be looking for a Kawi 650 twin... visualize the Verseys with MX suspension. Lots of engines around (in ninja form, if you're in the states) proven reliability with good power. I will build this bike some day, it has been on the list for quite a while.... mostly I need to find the engine local, 'cause shipping is a killer for me.

Big singles are already out there.... so what's the point doing that? Easier to upgrade suspension than graft an engine.

Edit: my "failed" attempt a couple years ago.... 440 is too small of an engine. Susupension is DR.

Does LC4 include the new 690? What about a motor out of a salvaged 1st year SM? Probably not "proven" and I guess the FI could be considered suspect.

Not a lot of bikes with right side output shaft.

The Tenere motor is the obvious suggestion if you want Japanese reliability plus FI. I see someone already suggested that. Can't imagine they are cheap or easily available but I guess these bikes get totslled too.

I thought the clear favorite would be the Rotax 654 as used in BMW F650 and G650 series bikes. I have got to admit, not exactly thinking out of the box, but it ticks most of the boxes. Pretty sure I even read on here about a guy in the middle east building some rally bikes out of KTM 660 frames with the BMW engine?

But I really like the idea of a twin. I only thought about the V-Strom and was sad that it would clearly not fit. Never even heard about the Versys before you guys mentioned it, but now that I have done some reading this thing seems perfect! Compact inline twin, 650cc, 6 speed, FI, 55-65mpg, 63HP/45ft-lbs, readily available for less than $1k even here in Europe. Now I just have to figure out if this thing will fit, especially since it's left hand output.

DR Big engine is a bit too old school for me, for similar power I could just put a big bore kit on my DR650 (might still do that one day). Yamaha 660 is also a good choice, but doesn't offer enough advantages over the Rotax to justify messing with left hand output. And as much as I like the new 690 LC4 (only ridden the carbed version so far), I would rather wait for KTM to iron out the bugs in the EFI, change to a wide ratio 6-speed, and finally sell it in the 690 Adventure version we have all been waiting for!

But I really like the idea of a twin. I only thought about the V-Strom and was sad that it would clearly not fit. Never even heard about the Versys before you guys mentioned it, but now that I have done some reading this thing seems perfect! Compact inline twin, 650cc, 6 speed, FI, 55-65mpg, 63HP/45ft-lbs, readily available for less than $1k even here in Europe. Now I just have to figure out if this thing will fit, especially since it's left hand output.

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On the other hand, you may consider getting an ER6 (naked version of versys with 5+hp), replace forks, swingarm and shock, transfer the exhaust from under the engine to the side for better ground clearance, lighten it here and there and you will end up with a sub 200kgr fully fuelled bike. The versys is 205 fully fuelled.